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I am mother and father, but ne...

I am mother and father, but never birth or nurse. I'm rarely still, but I never wander. What am I?

Correct answers: 61

The first user who solved this task is Djordje Timotijevic.

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I wish people would stop making fun of fat people

I wish people would stop making fun of fat people – they have enough sh-t on their plates.

Eddie Murphy (April 3 1961-)

Picture: Getty Images

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Crystal rectifier

In 1874, a paper by Ferdinand Braun (1850-1918) was published in the Annalen der Physik und Chemie describing his discovery of the electrical rectifier effect. He observed that certain crystals of metal sulphides have a larger or smaller resistance to an electric current, depending on its direction of flow. He used a galena crystal, a semiconductor material composed of lead sulfide. He found the rectifying effect especially true if at least one of the electrodes was a pointed wire. Thus, he had discovered the point-contact rectifier effect, the first semiconductor device. This effect wasn't used until over 30 years later in the form of the “cat's whisker”crystal radio detector which ultimately led to the point-contact transistor first produced in 1948.

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